History of China/Song Dynasty
The Song dynasty (宋朝), divided into Northern Song (960 - 1127 AD) and Southern Song (1127 - 1279 AD), was known for being militarily weak on purpose. After its first emperor was raised to the throne by his own army, he became wary of the threat generals pose to him. Thus a national policy of focusing on culture and studies rather than military strength was put into place, swapping generals around every few years to minimize loyalty to generals personally. Generals were also allocated troops only during times of war. A flourishing literary stage appeared as a result, creating many of the greatest Chinese writers and poets. Another focus was on concentrating power in the central authority and weakening regional governments, due to the fact that the previous Tang and period of fracture featured many coups and usurpation of power. Thus various checks and balances were placed on multiple levels of government to prevent one individual gaining too much power.
Because its military was weak, states set up by originally northern nomadic peoples like the Liao dynasty, Jīn dynasty and the Mongol empire was able to take over lands traditionally Chinese. The Jīn dynasty even raided and looted the capital Bianjing (汴京), captured the incumbent emperor and the previous one back to their homeland, and caused the Song court to flee south and establish a new capital, creating the Southern Song dynasty. The national hero Yue Fei (岳飛) was also born during this period. He was famous for leading his militia to fight against Jīn forces, almost recovering the old capital in the process. In the end the Song dynasty was conquered by the Mongols in 1279 AD.